﻿using System;
using System.Collections;
using System.Collections.Generic;
using Microsoft.Practices.CompositeUI.Properties;
using Microsoft.Practices.CompositeUI.Utility;

namespace Microsoft.Practices.CompositeUI.Collections
{
    /// <summary>
    /// 	Provides a read-only implementation of <see cref = "IDictionary{TKey,TValue}" />.
    /// </summary>
    /// <typeparam name = "TKey"></typeparam>
    /// <typeparam name = "TValue"></typeparam>
    public class ReadOnlyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
    {
        #region Fields & Properties

        private readonly IDictionary<TKey, TValue> _innerDictionary;

        #endregion

        #region Constructors

        /// <summary>
        /// 	Initializes a new instance of the <see cref = "ReadOnlyDictionary{TKey,TValue}" />
        /// 	class using the specified dictionary as the base.
        /// </summary>
        /// <param name = "innerDictionary"></param>
        public ReadOnlyDictionary(IDictionary<TKey, TValue> innerDictionary)
        {
            Guard.ArgumentNotNull(innerDictionary, "innerDictionary");
            _innerDictionary = innerDictionary;
        }

        #endregion

        #region Implementation of IEnumerable

        /// <summary>
        /// 	Returns an enumerator that iterates through the collection.
        /// </summary>
        /// <returns>
        /// 	A <see cref = "T:System.Collections.Generic.IEnumerator`1" /> that can be used to iterate through the collection.
        /// </returns>
        /// <filterpriority>1</filterpriority>
        IEnumerator<KeyValuePair<TKey, TValue>> IEnumerable<KeyValuePair<TKey, TValue>>.GetEnumerator()
        {
            return _innerDictionary.GetEnumerator();
        }

        /// <summary>
        /// 	Returns an enumerator that iterates through a collection.
        /// </summary>
        /// <returns>
        /// 	An <see cref = "T:System.Collections.IEnumerator" /> object that can be used to iterate through the collection.
        /// </returns>
        /// <filterpriority>2</filterpriority>
        IEnumerator IEnumerable.GetEnumerator()
        {
            return ((IEnumerable) _innerDictionary).GetEnumerator();
        }

        #endregion

        #region Implementation of ICollection<KeyValuePair<TKey,TValue>>

        /// <summary>
        /// 	Adds an item to the <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </summary>
        /// <param name = "item">The object to add to the <see cref = "T:System.Collections.Generic.ICollection`1" />.</param>
        /// <exception cref = "T:System.NotSupportedException">The <see cref = "T:System.Collections.Generic.ICollection`1" /> is read-only.</exception>
        void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
        {
            throw new NotSupportedException(Resources.DictionaryIsReadOnly);
        }

        /// <summary>
        /// 	Removes all items from the <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </summary>
        /// <exception cref = "T:System.NotSupportedException">The <see cref = "T:System.Collections.Generic.ICollection`1" /> is read-only. </exception>
        void ICollection<KeyValuePair<TKey, TValue>>.Clear()
        {
            throw new NotSupportedException(Resources.DictionaryIsReadOnly);
        }

        /// <summary>
        /// 	Determines whether the <see cref = "T:System.Collections.Generic.ICollection`1" /> contains a specific value.
        /// </summary>
        /// <returns>
        /// 	true if <paramref name = "item" /> is found in the <see cref = "T:System.Collections.Generic.ICollection`1" />; otherwise, false.
        /// </returns>
        /// <param name = "item">The object to locate in the <see cref = "T:System.Collections.Generic.ICollection`1" />.</param>
        bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> item)
        {
            return _innerDictionary.Contains(item);
        }

        /// <summary>
        /// 	Copies the elements of the <see cref = "T:System.Collections.Generic.ICollection`1" /> to an <see
        ///  	cref = "T:System.Array" />, starting at a particular <see cref = "T:System.Array" /> index.
        /// </summary>
        /// <param name = "array">The one-dimensional <see cref = "T:System.Array" /> that is the destination of the elements copied from <see
        ///  	cref = "T:System.Collections.Generic.ICollection`1" />. The <see cref = "T:System.Array" /> must have zero-based indexing.</param>
        /// <param name = "arrayIndex">The zero-based index in <paramref name = "array" /> at which copying begins.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "array" /> is null.</exception>
        /// <exception cref = "T:System.ArgumentOutOfRangeException"><paramref name = "arrayIndex" /> is less than 0.</exception>
        /// <exception cref = "T:System.ArgumentException"><paramref name = "array" /> is multidimensional.-or-The number of elements in the source <see
        ///  	cref = "T:System.Collections.Generic.ICollection`1" /> is greater than the available space from <paramref
        ///  	name = "arrayIndex" /> to the end of the destination <paramref name = "array" />.-or-Type cannot be cast automatically to the type of the destination <paramref
        ///  	name = "array" />.</exception>
        void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
        {
            _innerDictionary.CopyTo(array, arrayIndex);
        }

        /// <summary>
        /// 	Removes the first occurrence of a specific object from the <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </summary>
        /// <returns>
        /// 	true if <paramref name = "item" /> was successfully removed from the <see
        ///  	cref = "T:System.Collections.Generic.ICollection`1" />; otherwise, false. This method also returns false if <paramref
        ///  	name = "item" /> is not found in the original <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </returns>
        /// <param name = "item">The object to remove from the <see cref = "T:System.Collections.Generic.ICollection`1" />.</param>
        /// <exception cref = "T:System.NotSupportedException">The <see cref = "T:System.Collections.Generic.ICollection`1" /> is read-only.</exception>
        bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
        {
            throw new NotSupportedException(Resources.DictionaryIsReadOnly);
        }

        /// <summary>
        /// 	Gets the number of elements contained in the <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </summary>
        /// <returns>
        /// 	The number of elements contained in the <see cref = "T:System.Collections.Generic.ICollection`1" />.
        /// </returns>
        public int Count
        {
            get
            {
                return _innerDictionary.Count;
            }
        }

        /// <summary>
        /// 	Gets a value indicating whether the <see cref = "T:System.Collections.Generic.ICollection`1" /> is read-only.
        /// </summary>
        /// <returns>
        /// 	true if the <see cref = "T:System.Collections.Generic.ICollection`1" /> is read-only; otherwise, false.
        /// </returns>
        bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly
        {
            get
            {
                return true;
            }
        }

        #endregion

        #region Implementation of IDictionary<TKey,TValue>

        /// <summary>
        /// 	Determines whether the <see cref = "T:System.Collections.Generic.IDictionary`2" /> contains an element with the specified key.
        /// </summary>
        /// <returns>
        /// 	true if the <see cref = "T:System.Collections.Generic.IDictionary`2" /> contains an element with the key; otherwise, false.
        /// </returns>
        /// <param name = "key">The key to locate in the <see cref = "T:System.Collections.Generic.IDictionary`2" />.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "key" /> is null.</exception>
        public bool ContainsKey(TKey key)
        {
            return _innerDictionary.ContainsKey(key);
        }

        /// <summary>
        /// 	Adds an element with the provided key and value to the <see cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </summary>
        /// <param name = "key">The object to use as the key of the element to add.</param>
        /// <param name = "value">The object to use as the value of the element to add.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "key" /> is null.</exception>
        /// <exception cref = "T:System.ArgumentException">An element with the same key already exists in the <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" />.</exception>
        /// <exception cref = "T:System.NotSupportedException">The <see cref = "T:System.Collections.Generic.IDictionary`2" /> is read-only.</exception>
        void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
        {
            throw new NotSupportedException(Resources.DictionaryIsReadOnly);
        }

        /// <summary>
        /// 	Removes the element with the specified key from the <see cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </summary>
        /// <returns>
        /// 	true if the element is successfully removed; otherwise, false.  This method also returns false if <paramref
        ///  	name = "key" /> was not found in the original <see cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </returns>
        /// <param name = "key">The key of the element to remove.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "key" /> is null.</exception>
        /// <exception cref = "T:System.NotSupportedException">The <see cref = "T:System.Collections.Generic.IDictionary`2" /> is read-only.</exception>
        bool IDictionary<TKey, TValue>.Remove(TKey key)
        {
            throw new NotSupportedException(Resources.DictionaryIsReadOnly);
        }

        /// <summary>
        /// 	Gets the value associated with the specified key.
        /// </summary>
        /// <returns>
        /// 	true if the object that implements <see cref = "T:System.Collections.Generic.IDictionary`2" /> contains an element with the specified key; otherwise, false.
        /// </returns>
        /// <param name = "key">The key whose value to get.</param>
        /// <param name = "value">When this method returns, the value associated with the specified key, if the key is found; otherwise, the default value for the type of the <paramref
        ///  	name = "value" /> parameter. This parameter is passed uninitialized.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "key" /> is null.</exception>
        public bool TryGetValue(TKey key, out TValue value)
        {
            return _innerDictionary.TryGetValue(key, out value);
        }

        /// <summary>
        /// 	Gets or sets the element with the specified key.
        /// </summary>
        /// <returns>
        /// 	The element with the specified key.
        /// </returns>
        /// <param name = "key">The key of the element to get or set.</param>
        /// <exception cref = "T:System.ArgumentNullException"><paramref name = "key" /> is null.</exception>
        /// <exception cref = "T:System.Collections.Generic.KeyNotFoundException">The property is retrieved and <paramref
        ///  	name = "key" /> is not found.</exception>
        /// <exception cref = "T:System.NotSupportedException">The property is set and the <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" /> is read-only.</exception>
        TValue IDictionary<TKey, TValue>.this[TKey key]
        {
            get
            {
                return _innerDictionary[key];
            }
            set
            {
                throw new NotSupportedException(Resources.DictionaryIsReadOnly);
            }
        }

        /// <summary>
        /// 	Gets an <see cref = "T:System.Collections.Generic.ICollection`1" /> containing the keys of the <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </summary>
        /// <returns>
        /// 	An <see cref = "T:System.Collections.Generic.ICollection`1" /> containing the keys of the object that implements <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </returns>
        public ICollection<TKey> Keys
        {
            get
            {
                return _innerDictionary.Keys;
            }
        }

        /// <summary>
        /// 	Gets an <see cref = "T:System.Collections.Generic.ICollection`1" /> containing the values in the <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </summary>
        /// <returns>
        /// 	An <see cref = "T:System.Collections.Generic.ICollection`1" /> containing the values in the object that implements <see
        ///  	cref = "T:System.Collections.Generic.IDictionary`2" />.
        /// </returns>
        public ICollection<TValue> Values
        {
            get
            {
                return _innerDictionary.Values;
            }
        }

        #endregion
    }
}